This study investigated the effect of a three week supplementation of bilberry extract on glucose metabolism. Overweight volunteers (n = 16; BMI 31) were given three capsules of either 0.47 g bilberry extract (36% (w/w) anthocyanins) or placebo per day for three weeks in a double blinded cross over intervention.The ingestion of the bilberry extract decreased the OGTT AUCi for glucose (20%; p = 0.008) but not for insulin compared with the placebo. There was no change in anti-inflammatory markers (hsCRP, MCP-1, leptin), vascular health markers (Apo A1, sVCAM-1, sICAM-1), reducing potential/ radical scavenging capacity or faecal bacterial microbiota. In vitro studies showed that the bilberry extract decreased α-amylase activity (p < 0.0001), α-glucosidase activity (p < 0.0001) and glucose uptake (p < 0.0001).This study demonstrates that the ingestion of a bilberry extract over a three week intervention period reduces postprandial glycaemia without changes in insulin. This is probably due to reduced rates of carbohydrate digestion and/or absorption.
We are grateful to the Scottish Government Rural and Environment Science and Analytical Services (RESAS) for funding. We thank staff in The Human Nutrition Unit at the University of Aberdeen, Rowett Institute for their assistance with the study, and Indena S.p.A. for supplying the Mirtoselect® bilberry extract. We are grateful to the Kuwait government for additional funding. None of the authors had any conflicts of interest.
- Type 2 diabetes
- Glycaemic response
- BERRY ANTHOCYANINS